1. Field of the Invention
The present invention relates to magneto-optical disk apparatuses, and more particularly, to a magneto-optical disk apparatus that can adjust the position of the magnetic head with respect to the optical head.
2. Description of the Background Art
Attention is focused on a magneto-optical recording medium as a rewritable recording medium of great storage capacity and high reliability. The magneto-optical recording media are now applied as computer memories and the like. Standardization of a magneto-optical recording medium having a storage capacity of 6.0 Gbytes (AS-MO (Advanced Storage Magneto-optical Disk) standard) is in progress to be provided for actual usage. This magneto-optical recording medium of high density has the signal reproduced by the MSR (Magnetically Induced Super Resolution) method. More specifically, a laser beam is projected to transfer the magnetic domain of the recording layer of the magneto-optical recording medium to a reproduction layer and also forming a detection window in the reproduction layer to allow detection of only the transferred magnetic domain. The transferred magnetic domain is detected from the formed detection window.
Also, a magnetic domain enlargement reproduction technology has been developed. An alternating magnetic field is applied in reproducing a signal from a magneto-optical recording medium. The magnetic domain of the recording layer is enlarged to the reproduction layer by the laser beam and the alternating magnetic field while transferring to reproduce a signal. A magneto-optical recording medium that can record or reproduce signals of 14 Gbytes by virtue of this technology has been proposed.
It is expected that signals will be recorded or reproduced at further higher density, in which case the frequency of the alternating magnetic field is increased. It is therefore necessary to reduce the diameter of the coil that generates the magnetic field to approximately 20 .mu.m from the current diameter of approximately 200 .mu.m. In the case where the diameter of the coil is approximately 200 .mu.m, which is sufficiently greater than the diameter of the beam spot, it was only required to have the magnetic head roughly follow the optical head. However, in the case where the diameter of the coil becomes as small as approximately 20 .mu.m, any slight deviation of the center of the magnetic field from the center of the laser beam will impede proper recording or reproduction of signals.